PS uses scratch disk over RAM

Hi!
My Photoshop seems to use scratch disk instead of RAM.
Here's the scenario: I open up a file, convert it to a smart object and begin tiling it in a new document.
In task manager the memory usage for Photoshop.exe doesn't grov very much, it's around 300mb when I've duplicated my picture a few times. My scratch disk however has a temp file weighing 5gb! Task manager says also that the total usage of my physical memory is only 23%.
I have 8gb of RAM installed and I have my Memory Usage Settings set to Let Photoshop Use 5.4gb.
Now why is it that Photoshop uses my scratch disk even though I have lots of free RAM available? I thought Photoshop only uses scratch disk when the RAM is full?
I have Windows 7 64-bit with Photoshop CS5.

antevante wrote:
Now why is it that Photoshop uses my scratch disk even though I have lots of free RAM available? I thought Photoshop only uses scratch disk when the RAM is full?
It's unclear how big a file you are talking about-doesn't seem to be very big? Photoshop by default will always allocate scratch disk space upon launch. Whether or not it uses it depends on how much ram you have and how big the image is. Photoshop tries to keep it's operations in ram and only goes out to the scratch disk when needed.
However, Photoshop always uses scratch disk space to track history. If the history step is only a small area tile it doesn't take up much space. If it's the whole document, history can very quickly suck up the scratch disk space. By default the History is set to 20 steps, if you do something involving the entire file, the scratch disk usage could end up being 20X the original file size depending on the number of steps you have in history. Note, the History feature doesn't actually steal ram from Photoshop...it's only writing to the scratch disk but it can get real big real quick and you've found out.

Similar Messages

Scratch disks and RAM usage

i would like to understand the relationship between scratch disks and RAM usage in Photoshop.
While i was working on a fairly big psb file (2gb), photoshop kept prompting that I was out of memory, but in fact the utilization was only 75% (i had 16gbs total, photoshop was only using 7gb, and i allowed PS to use up to 14gb in total). when it says out of memory, it was actually my scratch disk at fault ( i only set 1 scratch disk, which was my 120gb SSD running out of space).
any idea how I can optimize PS to use up all my RAM first before even touching my scratch disk? (short of using a RAMdisk, please).
thanks!

I am curious about this also. I just reinstalled W-7--have 11 G of physical memory--a ton of hard drive empty space also, and I have been wondering why PS_CC is so slow--since basically I have only put my Security and Browser in addition to Adobe back on the Dell XPS computer..... At least now it does show the downloading percentage (like .psd file) , but that must be what is happening. I do think that some of these "frozen" screens I have been experiencing, was because the program was using scratch disk, instead of the Ram... I came up from CS-5, and can't describe it in detail, but just realize how slow PS-CC is in most everything. Going back and see if reallocating will help...

Photoshop not using scratch disk for PDF generation

Using Adobe Photoshop CC latest release - Set Scratch disk to S: drive. Photoshop consumes all of my c: drive using C:\users\<username>\AppData\Local\Temp for the temporary folder when generating a PDF.
How do I make Photoshop CC point to the S: drive for temp

I created a Junction with MKLINK from C:\users\<username>\AppData\Local\Temp to my solid state drive S:\MKLINK_TEMP so I was able to work around this.
It is taking over 30 minutes to generate a PDF from Photoshop
I upgraded to CC 2014 versions on all my applications yesterday as well.

New system with 32gb Ram.....CS5.5 using alot of scratch disk

Hi All,
Been away from these forums for a while.
OK. I have just built my new rig (Asus p9x79 pro, 32GB 1600Mhz DDR3, Intel 3820, old GTX285 1GB, Win7 pro.....many hard drives ) as I am working on a very big project producing 440x240cm200ppi digital drawings to be installed as lightbox artworks at the same size.
My old system just could not cope with the demands I was putting on it as It only had 12gb RAM. I have two scratch disks set up x1 30gb SSD (dedicated) and x1 240gb SSD ( has other stuff on it with 75gb free ). I am also using Photoshop CS5 Extended (updated) with RAM usage set to 80% (23976).
While I realise PS will still make use of the scratch disk despite the amount of RAM I was shocked to see the first drive (30gb) was almost full with 5gb space left when I loaded the PSB file with x9 layers. Looking at the meta data in Bridge it tells me the file size is 6.90GB with pixel dimensions of 34646x18898@200ppi. Windows reports that I am only using 20GB of my 32GB......
Shouldn't PS be using more RAM before going to the slower reads on a SSD? Windows Task Manager tells me I have 8150 RAM cached, 12310 RAM Available and 4215 RAM Free. If Photoshop is not using the 12GB would it be wise to make a 9GB RAMDISK for an addition boost...not even sure if that would work, but, I hate the feeling of having all that RAM and 1/3 not being used.

You referred to the answer to your puzzlement yourself when you typed "I realise PS will still make use of the scratch disk despite the amount of RAM" [emphasis added].
Photoshop creates the scratch disk the instant you open an image file or create a new one. It sets its initial size based on its size, number of layers, history states, etc., regardless of installed RAM. It starts using the scratch disks from the get go, moving stuff off of the scratch disk into RAM and viceversa as Photoshop sees fit.
When setting up a scratch disk, figure on at least 100 times (or more) the size of your largest file, multiplied by the number of files you keep open at any given time.
The total amount of scratch disk space on your two drives (30 GB + 75 GB) is not that large, as per the above calculation.
Just for reference, my dedicated primary scratch disk is a 300 GB physically separate internal hard drive, and I also have other drives set up as secondary, etc., hard drives. Other users have a lot more scratch disk space than I do. I normally have no more than two files open in Photoshop at once, occasionally three or four.
Also keep in mind that the percentage of memory you allocate to Photoshop is not a percentage of total installed RAM but of available memory at any given time after the OS and other applications you have running have grabbed the RAM they need. Therefore the calculation you made is not necessarily accurate.
As to creating a RAM disk, I supposed there's no harm in trying, but the real question is whether you are seeing any real performance problems now, rather than just calculating RAM figures that may or may not be that relevant in actual use.
Conceivably, you could also get a much larger SSD as your primary scratch disk.

When I try to use the internal hard drive as a scratch disk I get this error "unable to set scratch disk- the selected directory is on write protect or non-writable media. Any ideas on how to fix this. It only happens in fcp.

When I try to use the internal hard drive as a scratch disk I get this error "unable to set scratch disk- the selected directory is on write protect or non-writable media. Any ideas on how to fix this. It only happens in fcp.

By internal, I assume you're referring to your systems (boot) drive. Is it, by chance, a partitioned dive?
Also…although many people successfully use their systems drives as scratch disks, over time you'll have better results using a dedicated drive for your media.
Good luck.
Russ

Using SD Card or ExpressCard for Scratch Disk?

On my old laptop, I know that the patch for Photoshop CS3 allowed using scratch disks on removable media. But on my new computer, I've updated all the software and cannot get these drives to show in the list of scratch disks. The expresscard and SD reader are both built-in to the computer so they are pretty darn fast.
What trick do I have to perform to get these to appear and set them?
Thanks!
Kevin

Do you have any mapped network drives? One annoyance (on Xp) is that card reader drive letter assignment appears to ignore drive letters assigned to mapped network drives and will always start assignment with next drive letter after your local fixed drives. If you un-map network drives your card reader drive will "magically" appear. (I get around this problem by assigning mapped drives starting at high drive letters.)

Why do people set their scratch disk to a RAM drive?

From what I've read, the scratch disk in Photoshop is there so that if you become low on RAM, it will move data from the RAM to the allocated scratch disk...so why bother making that scratch disk the RAM when it'll just be going from the RAM...to the RAM? Am I missing something here?

Siderz95 wrote:
From what I've read, the scratch disk in Photoshop is there so that if you become low on RAM, it will move data from the RAM to the allocated scratch disk...so why bother making that scratch disk the RAM when it'll just be going from the RAM...to the RAM? Am I missing something here?
They're the ones missing something. It doesn't help to swap RAM to RAM. Now, it's possible people are talking about pointing their TEMP area to a RAM drive. There could be merit in that, but...
You want a real leg up? Get a good SSD for scratch, or take it even further and run your entire system off an array of SSDs.
-Noel

Photoshop RAM versus scratch disk/cache use

I recently ugraded my Mac to a new (to me) Power Mac G5 Dual 2GHz with 4GB RAM and two HDDs, one with OSX at 500GB and the other with 250GB (currently empty).
I followed the Adobe recommendations on setting up Photoshop CS2 for performance. I have my cache and scratch disk as the second (250GB) disk and therefore a different volume to the operating system. This disk is currently empty. In the cache settings, Photoshop sees 3072MB of the 4GB memory as available to it, and I have set the amount that PSCS2 can use to 100% (as Adobe states this is OK if you have 4GB or more of RAM).
With nothing else running on the Mac, when I open a tiff image of around 70MB, I can see in the status line at the bottom of the image window that the Efficiency is sometimes 100% but often drops to below 90% and down to 75% when doing image manipulations, which means that the scratch disk is being used (Adobe states that the Efficiency should be 95-100% when all actions are being done in RAM). However, when I look at the RAM status, there is still 2.5GB free, so PSCS2 has obviously not used all the RAM available to it when it starts using the scratch disk. I can also see that activity on the 250GB drive occurs when I do these manipulations, so the scratch disk is being accessed rather than actions being done in RAM
The only time I see the available RAM figure reduce is when I open multiple images. If I open ten 70MB tiff files then the RAM usage goes up a lot.
So my question is, why does PSCS2 use the scratch disk almost immediately when I manipulate an image even when I have told it to use 100% of the available 3072MB of available RAM? Have I missed a setting somewhere?
Any help or guidance appreciated.

Hi Buko
Thank you for your response. I did work through the optimisation guidelines before posting my message. I guess it is more about understanding why PSCS2 used the scratch disk when there is over 2GB of memory available, but I accept that it does what it does for good reason.
Could you let me know what the partitioning of my scratch disk will achieve? I did not see that in the optimisation guidelines, but I will definitely give it a try. I am interested to now what is actually does.
Thanks again, much appreciated.
Simon

*Noob* Which of these would I use for a scratch disk? How much Ram?

Hello, I am fairly new to Photoshop as I have used Lightroom ever since I've been a photographer. I recently got into Photoshop with the cloud as well as layering multiple exposures together. I never KNEW anything about scratch disk, until yesterday.
First let me stress, please answer my questions in layman's terms. I search the net before I start a topic on a forum and I read a lot of answers that seem to be responding to people who have a general idea of what is already going on. Remember, I DO NOT. Here are my questions:
A:If the scratch disk acts like RAM, do I need to allow it to use any of my ram at all? If so, how much? I have two Macbook Pro's, they are the highest model Apple makes, both have SSD drives, Quad Core i7's, etc. I unchecked my Macbook hard drive and told it to use an external SSD drive that is plugged in via USB 3.0. Would it be better to use an HDD instead of SDD? I have lots of hard drives to choose from due to being a music producer.
B:When I exit the program does it delete all the data it created? This question is two fold, does it delete it regardless if I saved the project or not? If I save the project does it stay there? What if I delete the original photo, was the photo imported into photoshop upon camera raw?
C: Like question A, how much ram do I choose? I have 16GB of Ram in each of my MacBooks.

OK, I have now copied your hillbilly text and pasted it into a text editor to change the typeface so I can read it.
I'll try to address the lose ends here.
A:…I have two Macbook Pro's, they are the highest model Apple makes…
Please forgive me for not being impressed. I just happen to consider any laptop a sub-optimal choice for Photoshop photography work. My personal opinion. (Please don't ask me why.)
, both have SSD drives,… I unchecked my Macbook hard drive and told it to use an external SSD drive that is plugged in via USB 3.0. Would it be better to use an HDD instead of SDD?…
I assume you are talking about using the external drive as your primary scratch disk, not as your boot disk. That is the appropriate thing to do. HD or SSD will both do the job fine, as long as they're physically separate, dedicated Photoshop scratch disks.
Obviously the internal drive will be your boot disk. Adobe applications really like to reside on the boot disk, the drive where the OS resides.
B:When I exit the program does it delete all the data it created?
This question is two fold, does it delete it regardless if I saved the project or not?
If I save the project does it stay there? What if I delete the original photo, was the photo imported into photoshop upon camera raw?
NOTHING is ever imported into Photoshop, ever. You use Photoshop to open your files exactly where you put them in the Apple Finder. And you save them wherever you wish, in the Finder as well. Your images will always reside in the Finder.
You don't import files into Adobe Camera Raw either. You open them in or with ACR.
Of course you need to save your data, not only when you quit the application, but at frequent intervals while you're working on it. Nothing you saved will be deleted by Photoshop. How can you even conceive and ask such a question? ?? !
If you ever try to close a file or the application when you have open, unsaved files, the application will ask you for confirmation in an unmistakable way.
Your images will always reside in the Finder, wherever you put them.
Photoshop does not have the abominable "Libraries" scheme that made me detest Lightroom when I tried it. Nor does Photoshop hide your image files in "packages" like the even more abominable iPhoto does.
Please forget anything you may be accustomed to in Lightroom and/or iPhoto, and approach Photoshop with a fresh mind, respecting it like the granddaddy of image editors it is.
C: Like question A, how much ram do I choose? I have 16GB of Ram in each of my MacBooks.
Again, you don't "choose RAM", instead you select a percentage of dynamically changing Available Memory (not RAM; see above) to allow Photoshop to use. Leave at around 70%.
Please see the following post for an important tip.

Photoshop CS4 does NOT use RAM as scratch disk

Photoshop CS4 does NOT use RAM as scratch disk
as far as I can tell.
I have 20 GB RAM and still Photoshop uses the hard disk as scratch disk.
(OS = Win 7 64).
Can I force the use of RAM as scratch disk?
/Larry

Hi PECourtejoie,
I really try to understand this, please.
I don't know if 'Hitting the hard disk brings unacceptable slowdowns in my workflow'.
Because I don't know what unacceptable slowdowns are.
Any operation in Phshp takes time, and you always want it to go as fast as possible..
I know that if Phshp only worked against RAM instead of constantly saving to (and reading from) the hard drive it ought to go faster.
But I still don't know if this is the case, because there is a constant use of a tempfile on the hard drive's Scratch disk!
So far I understand that Phshp may BOTH work in RAM AND save data to the hard drive Scratch disk.
It could be possible that the writing to the hard disk happens when Phshp is idle from other tasks and that the reading only happens when data has disappeared from the Cache in RAM.
That could be a scenario where a Scratch disk on Hard drive doesn't interfere with Phshps performance, and an explanation why we should not bother about the Scratch disk on the hard drive.
But I would very much like to have some confirmation on this, IF this is the explanation of how the Scratch disk on a hard drive works without influencing Phshp's performance??
Everybody just seem to assume that Photoshop uses (some) parts of RAM as work space - I just need a better understanding of this. And some correct descriptions.
/Larry

How to use RAM as scratch disk

Hi,
I am very uncertain about this.
I have a PC with RAM 20GB, Win 7 64 bits. Photoshop CS4.
I have set a hard disk partition as a primary scratch disk.
In the Preferences I have available RAM: 18488 MB
I let Photoshop use 13000 MB (70%).
Every time that I do something on a picture in Photoshop the size of the Photoshop temporary file on the hard disk scratch partition grows.
It seems that my Photoshop uses the hard drive as the scratch disk.
I thought that Photoshop automatically should use extra RAM as a scratch disk.
Have I forgotten to do some setting, or is this the normal behaviour?
How can I force the scratch disk to happen in RAM?
Thanks
/LArry

LarryM01 wrote:
…Every time that I do something on a picture in Photoshop the size of the Photoshop temporary file on the hard disk scratch partition grows…
Perfectly normal, expected behavior.
Photoshop always uses a scratch disk, from the very instant you open an image file or create a new document. Always. No exceptions.
LarryM01 wrote:
…I have set a hard disk partition as a primary scratch disk…
If that's a partition of your boot drive, it's futile and you're much better off leaving the boot drive unpartitioned so as to not limit either the Photoshop scratch disk or the OS swap files. There's nothing to gain because the OS swap files and Photoshop's scratch disk are still competing for the use of the one set of read/write heads.
Bad move. You're just potentially limiting either the Photoshop scratch disk or the OS swap files.
Wo Tai Lao Le
我太老了

CS6 Macintosh RAM, Video Card, Scratch Disk?

I upgraded to the CS6 Master Collection in December and just installed it a couple days ago. I must say I love the new tiling options!
I am running the software, mostly Photoshop and Illustrator, on a 2.8GHz Quad-Core Intel Xeon Mac Pro running 10.7.5. I am looking to improve processing times as I am starting to work with bigger images for graphics work, which are usually 75-100MB, but with some of them reaching the 200-300MB range.
I have some questions regarding computer upgrades:
1. Increasing the current 16GB of memory to the maximum of 16GB would run about $557.00:
a. Would I see much of a speed increase when using PS or Illustrator to work on a single file given the file sizes?
b. Would there be much of a benefit in speed when using both at the same time; for example, while waiting for Illustrator to process a large image I work on another image in PS.
2. Given the amount of RAM does a seperate scratch disk provide any benefit? I've used them on PowerPc Macs, but those only had 2GB RAM and a lot slower graphics cards.
3. Would there be much of speed increase by upgrading the graphics card from the current ATI Radeon HD 5770 to a ATI Radeon HD 5880? That would likely be the only card I'd ever upgrade to as it has the same basic monitor connectors as the 5770. The 5780 would run about $480.
4. I recently exported a AI file as a png file. If you examine the file's details using the Macintosh menu item "File: Get Info" it indicated that the file was 46,666 x 46,666 pixels with a size of 67.6MB, yet when I attempted to open it in PS I received a out of memory error even though PS indicated that there was over 15GB of memory available. The file would VERY slowly open in Macintosh's default Preview application so I don't think the file was corrupt.

Thanks for the information.
1. Sorry, should have stated 16GB to 48GB.
2-3. Did some further research on gpu and related items and I see that Illustrator depends upon RAM and a scratch disk while PS utlizes these plus the GPU. So upgrading the graphics card could benefit PS, especially if its listed upon the listed on tested cards:
http://forums.adobe.com/thread/979969
4. I think have may detected a bad RAM card in slot #2 so this may be the cause.
I'll think I'll max the ram and install a scratch HD for now.

Need Urgent Help! RAM and Scratch Disk Problem

I was recently working on making a gigapixel panorama. I made the panorama in AutopanoGiga and rendered it as a .psb. I went to go fix some stuff on the file and the first thing I did was content aware fill. The panorama ended up being 4 gigapixels before cropping. So I wanted to try content aware fill on a small portion of the image. I am using a 12-core Mac Pro with 20GB 1333 MHz RAM. I have an SSD as my boot drive and four 2TB mechanical drives, none of which in a RAID.
When I first installed Photoshop on my Mac Pro, I went into the preferences to change the memory and scratch disk settings. The first thing I did was set Photoshop to use 12GB RAM. Then I went to the scratch disk and noticed that only my SSD was set up as a scratch disk. So I unchecked the activate box next to the SSD, activated all 4 other drives, and moved the SSD to the bottom of the list.
So I started content aware fill and saw that it would take some time. So I left and when I came back a little over an hour later, Photoshop gave me a message saying that the scratch disk was full and it couldn't complete the content aware fill. Why did this happen????? I deactivated my SSD and activated four separate 2TB drives!
I went on MacRumors Forums and asked some people, and the only advice I got was to reset my settings. I did that, redid my scratch disk settings, and it is still using my SSD as the scratch disk! Can someone please help??

CAF is processor and memory intensive... most of the flashy demos of this feature have been on much smaller images.
CAF has also been known to kick RAM errors when it simply farts and dies. Is CS5 fully patched?
Wear a helment when you try to hit your head on the ceiling.

Weird RAM/Scratch Disk issue

Having a weird memory problem with Photoshop CS4 on my G5 Quad.
Let me see if I can explain this properly....
When I open up a file in Photoshop, I notice that the available space on my hard drive reduces (info at the bottom of any Finder window). Essentially, it's using the scratch disk.
I would expect this with a very large file that exeeds the amount of ram in the machine. But it does it even with files of 5-10 Mb. It appears to me (just a guess) that Photoshop isn't using RAM when opening or manipulating a file. Though I have more than enough to open it.
Even when I close the file, or "purge all" from PS's edit menu, my available disk space does not come back. Only when I quit out of Photoshop completely, will it come back.
Make sense?
No other application seems to be having this issue. Any ideas on what might be causing this?
I've run Apples Disk Utility, and everything came out fine. Ran TechTool Deluxe, and no problems there either. Hoping maybe I'm just missing some piece of the puzzle first, before I uninstall/reinstall Photoshop.
System specs:
G5 Quad (2.5 GHz)
4 GB RAM
OSX 10.5.8
Photoshop CS4 (11.0.1)
Memory usage set to allow up to 70% (but doesn't seem to matter what I set it to)

This is normal.
Photoshop needs to allocate scratch space for data, in case it needs to write that data to disk later -- otherwise you would randomly fail with "out of scratch space" in the MIDDLE of an operation.
Photoshop is using RAM, but needs to allocate the scratch space, and make sure the allocation succeeded.
And yes, RAM and scratch space get reused, so rarely decrease.
Other applications that deal with datasets larger than RAM will have the same issues.
And technically your OS swapfiles do the same things.

Can I use my old g5 tower as a scratch disk for my Macbook Pro for Photoshop?

I just made the laptop jump away from towers and am a little shocked by how much difference a smaller scratch disk makes. Can I use my old tower as a scratch disk to help out my new Macbook Pro?
Any other tweaks I can do to speed up large files in Photoshop? Should I bump up the ram usage by Photoshop above the recommened percentage?

Hm. It sounds like you know what you are talking about, and apparently I don't. I was just going to plug in a firewire cable to both and hoped that magically scratch disk would appear as an option for my tower.
Cant I somehow boot the tower as using as a hardrive only? Or applesharing or something else?

PS uses scratch disk over RAM

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